Device for injection-moulding a part

Abstract

A tooling for injection-molding a part, the tooling including two cavity blocks each including a cavity formed therein of a shape corresponding to a shape of a part that is to be molded once the cavity blocks have been superposed. At least one of the cavity blocks includes a mechanism for positioning a core, which mechanism includes at least one bearing surface for bearing against the core and at least one presser screw screwed into a threaded passage of the cavity block for purpose of holding the core in position against the bearing surface. The tooling further includes a force-limiter limiting force applied to the core by the presser screw.

The invention claimed is: 
     
       1. A tooling for injection-molding a part, the tooling comprising:
 two cavity blocks each including a cavity formed therein of a shape corresponding to a shape of a part that is to be molded once the cavity blocks have been superposed; 
 at least one of the cavity blocks including means for positioning a core, which means comprises at least one bearing surface for bearing against the core and at least one presser screw screwed into a threaded passage of the cavity block such that an end portion of the at least one presser screw clamps the core in position against the bearing surface; and 
 force-limiter means for limiting a force applied to the core by the presser screw, wherein 
 the force-limiter means includes torque-limiter means arranged between a tightening head and a threaded portion of the presser screw and configured to transmit clamping torque from the head to the threaded portion so long as the torque is less than a determined value, and to decouple the head from the threaded portion when the torque is greater than the determined value. 
 
     
     
       2. A tooling according to  claim 1 , comprising two bearing surfaces for bearing against the core and two presser screws arranged facing the bearing surfaces and configured to hold the core in position against the two bearing surfaces, the screws extending substantially perpendicularly to each other and each including torque-limiter means. 
     
     
       3. A tooling according to  claim 1 , wherein the determined value of the clamping torque beyond which the head is decoupled from the threaded portion of the presser screw lies in a range 0.1 Nm to 5 Nm, or is about 1 Nm. 
     
     
       4. A tooling according to  claim 1 , including a stationary bottom cavity block and a movable top cavity block, the bearing surface being formed in the cavity of the stationary cavity block, the presser screw being mounted on the stationary cavity block. 
     
     
       5. A tooling according to  claim 1 , wherein the two cavity blocks are mounted to pivot relative to each other about a pin between a molding position in which the two cavity blocks are superposed, and an un-molding position in which the two cavity blocks are spaced apart. 
     
     
       6. A tooling according to  claim 5 , wherein at least one of the cavity blocks is mounted to pivot about the pin via at least one rolling bearing, or a ball bearing. 
     
     
       7. A tooling according to  claim 1 , wherein the determined value is in the range 0.1 Nm to 5 Nm. 
     
     
       8. A tooling according to  claim 1 , wherein the determined value is about 1 Nm. 
     
     
       9. A tooling according to  claim 1 , further comprising:
 an injection channel that carries wax into the cavities around the core. 
 
     
     
       10. A tooling according to  claim 1 , wherein the cavities define a shape of a blade having an airfoil and a platform. 
     
     
       11. A tooling according to  claim 1 , wherein the core defines a shape of a cooling circuit.